PIC16F628A Test Setup.
Fig. 1
Click here for larger image.

PIC16F628 Rotary Encoder Operates Stepper Motor Controller

For more background on stepper motor control and Easy Driver see the following:

How to Connect Easy Driver Micro-Stepper Controller to Arduino
Rotary Encoder Used with Arduino Interrupts

To see wiring schematic for the encoder.

YouTube video see PIC16F628 PIC Using Rotary Encoder to Operate Stepper Motor

The program works by polling RA0 for a low, then checks state of RA1, which will determine direction. Then 200 step pulses are sent to RB5, which will turn this particular motor (1.8 degrees per step) 360 degrees for every position (20 in this case for 360 degrees) on the encoder.

RA0 and RA1 both have Schmitt trigger inputs, one should also connect a .0047 uF cap to ground from each pin.

Download ASM code a5.asm.

See How I got into Electronics

You Tube Videos for this Series
Home Built PIC Development Board
PIC16F628 PIC Using Rotary Encoder to Operate Stepper Motor
Using a Serial ADC with PIC16F628
Calculating Pulse-Width Modulation with a PIC
PIC16F84A-628A Hardware Time Delays
PIC16F84A-628A Timer Interrupt Delays
PIC16F84A-628A Pullups and Interrupts
PIC16F84A-628A Hardware Interrupts Tutorial

Projects using PIC16F628:
Home Built PIC16F628 Prototyping Board
Exploring the Microchip PIC in Assembly
Using a Microchip PIC with TLC548 Serial ADC
Controlling PIC Pulse Width Modulation with a Serial ADC
Using TMR0 on a PIC with Interrupts
External Clock Crystal with PIC16F628 TMR1 Generates Interrupt
PIC Using Rotary Encoder to Operate Stepper Motor
PIC16F628 Pulse Width Modulation Controls Brightness of LED
Another way to Turn On-Off PWM in a PIC
TLC548 Serial ADC Spec. Sheet

Programming PIC16F84A-PIC16F628A Interrupts by Example
PIC16F84A-PIC16F628A Pull Up Resistors with Interrupts
Programming PIC16F84A-PIC16f628a Timers by Example
Programming PIC16F84A-PIC16F628A TMR0 Interrupts
Programming PIC16F84A Software Delay Routines by Example